Interaction between the ciliary gene KIF3A and food sensitization is associated with an increased risk for asthma in children with and without early eczema by the age of 7 years, according to a study published in Clinical & Experimental Allergy.
Participants in the prospective Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) birth cohort were included in the analysis (N=505). The CCAAPS contains longitudinal outcomes data for eczema and asthma as well as prospective timing of sensitization to foods and aeroallergens data. Participants in the cohort were examined for allergic disease at 1, 2, 3, 4, and 7 years of age. Researchers also obtained genotyping data of KIF3A for all participants.
A total of 2 high-risk groups were found, including groups with early eczema (diagnosis at ages 1, 2, or 3 years) and without early eczema. Individuals with early eczema were more likely to be sensitized to food allergens. Conversely, individuals without early eczema were more likely to be polysensitized to aeroallergens. Children with eczema had an increased asthma risk by age 7 when the KIF3A rs12186803 risk allele interacted with food sensitization (P =.02). Children without eczema had an interaction between rs12186803 and aeroallergen sensitization, which was associated with an increased risk for asthma (P =.007).
Limitations of the study included the lack of allergen testing for allergens other than milk and egg.
“[T]he atopic march only represents one phenotype of asthma, and there is another early life high-risk group for asthma of children with early poly-[aeroallergen sensitization] without eczema,” the researchers wrote. “This group may be overrepresented in the African-American population and has been often marginalized with the focus on the atopic march phenotype. Interestingly, asthma risk in both groups was modified by the KIF3A risk allele.”
Johansson E, Biagini Myers JM, Martin LJ, et al. Identification of two early life eczema and non-eczema phenotypes with high risk for asthma development [published online March 4, 2019]. Clin Exp Allergy. doi:10.1111/cea.13379